Tests for ApiServlet

- tests for login
- loginSuccessResponse test for xml and json

Signed-off-by: Laszlo Hornyak <laszlo.hornyak@gmail.com>
removed commented-out code

Signed-off-by: Laszlo Hornyak <laszlo.hornyak@gmail.com>
StringBuffer replaced with StringBuilder in ApiServlet

Signed-off-by: Laszlo Hornyak <laszlo.hornyak@gmail.com>
StringBuffer replaced with StringBuilder in ApiServerService

Signed-off-by: Laszlo Hornyak <laszlo.hornyak@gmail.com>